The present invention relates to absorbent articles, such as diapers or incontinence guards, which seal more effectively against the wearer than earlier known articles of this kind.
An absorbent article of the kind to which the invention relates comprises a liquid-impermeable sheet which is intended to lie distal from the wearer in use, an absorbent body, and an upper liquid-permeable sheet which is intended to lie proximal to the wearer in use. When the absorbent article is a diaper or an incontinence guard it will also include flexible side flaps or wings that extend laterally outside the absorbent body on both sides thereof, and elastic elements that extend longitudinally along the free side-edges of the side-flaps at least within that part which is intended to form the crotch part of the article in use, said side flaps and elastic elements functioning to enable the absorbent article to be fitted to the wearer. These elastic elements function as leg elastic when the article is worn. Thus, when the article is donned, the elastic elements will be stretched and hold the side flaps tightly against the wearer.
Currently available absorbent articles have very high absorbencies and can also retain liquid under pressure. The most serious problem occur in the event of rapid liquid discharges. In such cases, it is necessary for a large volume of liquid to pass first through the top liquid-permeable sheet and then be absorbed by and dispersed in the absorbent body. This does not take place instantaneously. The time taken for the liquid to pass through the top sheet may be from about 1 to 2 minutes, during which time liquid will run out to the edges of the article and leak therefrom. These problems are addressed with the aid of so-called liquid barriers or inner cuffs or side-flaps that are intended to resist liquid leakage in the event of rapid liquid discharges. The originally used cuffs where intended primarily to retain faeces and were formed by folding a part of the liquid-permeable top sheet around an elastic thread. In recent times, manufacturers have begun to produce the cuffs from a liquid-impervious material in order to also retain liquid.
When the leg elastic on the absorbent article is stretched and the article fastened on the wearer, the elastic element of the liquid barriers will also be stretched, thereby raising the barriers up. The elastic element of the barriers will hold the barrier edges under tension against the wearer. The upstanding liquid barriers then form beneath the wearer a xe2x80x9ctroughxe2x80x9d in which a rapidly discharged large volume of urine can be accommodated during the time required for the liquid to pass through the top liquid-permeable sheet. Attempts to improve the effectiveness of such liquid barriers have hitherto been directed towards the use of denser materials and towards flaps of sufficiently large size.
One drawback, however, is that liquid will rise above the brim of the barriers and leak out when the volume of liquid discharged is excessive or when the wearer sits or lies down such as to press together the space between the upstanding liquid barriers.
Thus, currently available absorbent articles, such as diapers or incontinence guards, may include along the outer longitudinal edges of the article sealing edges that are intended to lie tightly around the wearer""s thighs and to shape the article to the wearer""s body, as well as a pair of inner cuffs or liquid barriers which lie inwardly of the outer longitudinal edges and which are intended to form an impervious barrier against rapidly discharged liquid that is not absorbed immediately by the absorbent body of said article. These inner cuffs shall thus be capable of withstanding a relatively high liquid pressure over a limited time period in the order of a minute or so. The liquid will have been absorbed by the absorbent body when this time period has passed. Side cuffs may also be used on sanitary napkins, for instance. Also available are articles which include transverse cuffs that seal-off the transverse edges of the absorbent body.
Absorbent articles which lack the aforedescribed inner liquid barriers are also available. In these cases, the outer longitudinal sealing edges form the sole liquid barriers of the absorbent body.
Also available are absorbent articles which include a liquid-impermeable sheet that is intended to lie proximal to the wearer in use and that incorporate elastic threads for shaping the article to the wearer""s body. This liquid-impermeable sheet includes at least one aperture which is intended to register with the wearer""s anus and urethra orifice when the article is donned. Elastic is provided around at least a part of the perimeter of the aperture or apertures so as to shape the edges of the aperture against the wearer and to form a seal. Situated beneath the liquid-impermeable sheet is an absorbent body which is enclosed between a liquid-permeable sheet and a liquid-impermeable sheet, such that the absorbent body will hang down beneath the wearer with the liquid-impermeable sheet lying distal from the wearer.
The inner cuffs are comprised partly of a thin barrier sheet of essentially liquid-impervious and inelastic material, e.g. nonwoven material, and an elastic device which puckers or gathers together that edge of the liquid barrier which lies against the wearer. The unresilient, inelastic material is fastened along one longitudinal edge either to the top liquid-permeable sheet, so that no liquid can pass between these two sheets, or to the bottom liquid-impervious sheet along the side-edge of the article. The elastic device is fastened along the other edge of the unresilient material so as to gather the liquid barrier together and therewith form a puckered edge, which will extend or stretch partially when the article is donned. The puckered edge is normally comprised of an elastic thread which is placed in a channel in the inelastic material, said channel being formed by folding over and welding one edge of the material. When the absorbent article is donned, the puckered edge will stretch partially, the extent of this stretch being dependent on the size of the wearer and how the article is donned. It is also possible to use an elastic element consisting of an elastic film. In this case the elastic element will not be enclosed in a channel, but will be fastened, in a prestretched state, along a first longitudinal side-edge against the other side-edge of the unresilient material, the second side-edge of the element being free and abutting the wearer when the article is donned. Further, the first longitudinal side-edge of the elastic film may be fastened, in a prestretched state, directly against the top liquid-permeable sheet or the bottom liquid-impermeable sheet. In this case, the barriers will consist of solely the elastic film.
Another type of sealing edges are described in U.S. Pat. No. 5,445,627. A sanitary napkin is provided with a pair of elastically stretchable flaps adjacent transversely opposite side edges. The flaps are in the form of straps and rising from a backsheet. Adhesives are applied on the top surface of said flaps so that the flaps may be adhesively fastened to the user""s skin. The intention is to compensate for a shift of the basic body of the napkin relative to the wearer""s body. Thus, the napkin is made to adhesively adhere to the user""s skin. This is not a case where an elastic barrier element is stretched against the wearer-to obtain a good sealing effect.
In WO-A-9516424 a similar type of adhesive attachment of a sanitary napkin to the user is described. The object of the invention described is to provide an absorbent article that is adhesively secured to the wearer""s body so that it will closely conform to and fit the external body surfaces. This is obtained by an absorbent article including an absorbent and a body side adhesive secured thereto and exhibiting suitable adhesion properties to skin but which can be removed without appreciable discomfort.
Neither U.S. Pat. No. 5,445,627 nor WO-A-9516424 describes elastic cuffs or liquid barriers which are stretched when the article is fastened on the wearer and where the elastic element will hold the barrier edges under tension against the wearer.